Dorywalska Magdalena, Strop Pavel, Melton-Witt Jody A, Hasa-Moreno Adela, Farias Santiago E, Galindo Casas Meritxell, Delaria Kathy, Lui Victor, Poulsen Kris, Loo Carole, Krimm Stellanie, Bolton Gary, Moine Ludivine, Dushin Russell, Tran Thomas-Toan, Liu Shu-Hui, Rickert Mathias, Foletti Davide, Shelton David L, Pons Jaume, Rajpal Arvind
†Rinat Laboratories, Pfizer Inc., 230 East Grand Avenue, South San Francisco, California 94080, United States.
‡Worldwide Medicinal Chemistry, Pfizer Inc., 445 Eastern Point Road, Groton, Connecticut 06340, United States.
Bioconjug Chem. 2015 Apr 15;26(4):650-9. doi: 10.1021/bc5005747. Epub 2015 Feb 20.
The systemic stability of the antibody-drug linker is crucial for delivery of an intact antibody-drug conjugate (ADC) to target-expressing tumors. Linkers stable in circulation but readily processed in the target cell are necessary for both safety and potency of the delivered conjugate. Here, we report a range of stabilities for an auristatin-based payload site-specifically attached through a cleavable valine-citrulline-p-aminobenzylcarbamate (VC-PABC) linker across various sites on an antibody. We demonstrate that the conjugation site plays an important role in determining VC-PABC linker stability in mouse plasma, and that the stability of the linker positively correlates with ADC cytotoxic potency both in vitro and in vivo. Furthermore, we show that the VC-PABC cleavage in mouse plasma is not mediated by Cathepsin B, the protease thought to be primarily responsible for linker processing in the lysosomal degradation pathway. Although the VC-PABC cleavage is not detected in primate plasma in vitro, linker stabilization in the mouse is an essential prerequisite for designing successful efficacy and safety studies in rodents during preclinical stages of ADC programs. The divergence of linker metabolism in mouse plasma and its intracellular cleavage offers an opportunity for linker optimization in the circulation without compromising its efficient payload release in the target cell.
抗体-药物连接子的全身稳定性对于完整的抗体-药物偶联物（ADC）递送至表达靶点的肿瘤至关重要。在循环中稳定但在靶细胞中易于加工的连接子对于所递送偶联物的安全性和效力都是必需的。在此，我们报告了一系列基于奥瑞他汀的有效载荷通过可裂解的缬氨酸-瓜氨酸-对氨基苄基氨基甲酸酯（VC-PABC）连接子位点特异性连接到抗体不同位点后的稳定性。我们证明，偶联位点在决定VC-PABC连接子在小鼠血浆中的稳定性方面起着重要作用，并且连接子的稳定性在体外和体内均与ADC的细胞毒性效力呈正相关。此外，我们表明小鼠血浆中的VC-PABC裂解不是由组织蛋白酶B介导的，组织蛋白酶B被认为是溶酶体降解途径中主要负责连接子加工的蛋白酶。尽管在体外灵长类动物血浆中未检测到VC-PABC裂解，但在小鼠中连接子的稳定化是在ADC项目临床前阶段设计成功的啮齿动物疗效和安全性研究的重要前提。小鼠血浆中连接子代谢的差异及其细胞内裂解为在不影响其在靶细胞中有效释放有效载荷的情况下在循环中优化连接子提供了机会。
